scholarly journals A Helical Charge Simulation based 3-D Method for Calculating AC Stranded Conductor’s Corona Loss in the Corona cage

2017 ◽  
Author(s):  
Yunpeng Liu ◽  
Shilong Huang ◽  
Shugang Liu ◽  
Daran Liu ◽  
Zhicheng Huang
Keyword(s):  
Transmission Lines ◽  
Axial Direction ◽  
Simulation Method ◽  
Calculation Model ◽  
Loss Calculation ◽  
Simulation Based ◽  
Measurement Results ◽  
Calculation Results ◽  
Ac Transmission ◽  
Design Factors

Corona loss generated from conductors is one of the important design factors on ac transmission lines. Based on helical charge simulation method, the 3-D corona loss calculation model considering the conductors’ outer strands in the corona cage is established. With regard to 2-D corona-loss calculation method, the calculation model proposed in this paper can take the electric field strength’s nonuniformity along the axial direction of stranded conductor into consideration, furthermore, it can also calculate the corona loss when the conductor has sag. The calculation results of the LGJ-300/40 and LGJ-400/35 in the small corona cage well coincide with the measurement results, which indicates that the corona-loss calculation model is appropriate. In addition, the corona loss of the bundle conductors 4 × LGJ720 with sag in UHV corona cage is also analyzed.

Study on the Influence Factors of Dry Hollow Parallel Reactor Loss

2015 ◽  
Vol 734 ◽  
pp. 887-892
Author(s):  
Xiao Bing Guo ◽  
Xiang Yu Tan ◽  
Yong Hong Wang ◽  
Yan Wang ◽  
Kun Ming Zhao ◽  
...  
Keyword(s):  
Influence Factors ◽  
Calculation Model ◽  
Partial Loss ◽  
Loss Calculation ◽  
Local Branch ◽  
Individual Branch ◽  
Calculation Results ◽  
Reactor Production ◽  
Main Factor ◽  
Parallel Reactor

Reactor individual branch loss mutation is one of the important reasons leading to local temperature too high. In order to explore process deviation for dry type hollow shunt reactor loss amplification effect, this paper is establish a loss calculation model of dry-type air-core reactor as the tool, Comparative analysis relationship between the four common types of process deviation and the local branch loss. Calculation results show that the number of turns deviation are the main factor influencing the reactor partial loss, So the reactor production winding process should strengthen the control of the number of turns deviation.

Calculation of Capacitance Variation in Corona Cage

2015 ◽  
Vol 740 ◽  
pp. 405-410
Author(s):  
Xiao Ming Li ◽  
Yong Zhong Pan ◽  
Hong Jun Li ◽  
Jie Shuai Ren ◽  
Po Hu ◽  
...  
Keyword(s):  
Electric Field ◽  
Transmission Lines ◽  
Simulation Method ◽  
Calculation Model ◽  
Meteorological Conditions ◽  
Charge Simulation Method ◽  
Tight Coupling ◽  
Space Charges ◽  
Supplementary Method ◽  
Capacitance Variation

Corona cage is an important supplementary method for studying corona phenomenon, which is an indispensable for designing transmission lines. In this paper, the bundle conductors are chosen as research objects and the charge simulation method (CSM) is applied to build calculation model, using line electric charges to simulate bundle conductors, walls of corona cage and space charges. The method of tight coupling of electric field and potential is first introduced in corona processing, in which the Kaptzov hypothesis is directly applied to establish equations of charge - electric field and charge - electric potential. In addition, in order to analyze the capacitance value variation of corona cage when corona onset occurs, the emission, migration and composite process of space charges is simulated. Finally, 4, 8, 12 conductors in corona cage under different meteorological conditions are modeled, and the research results are analyzed. This research can also be applied to model corona cage and high voltage transmission lines at different voltage levels and different bundles under different meteorological conditions.

Effect of Temperature Distribution on Critical Speeds of a Dual-Rotor System

2014 ◽  
Vol 709 ◽  
pp. 21-24
Author(s):  
Gui Yu Xin ◽  
Ke Ming Wang ◽  
Mei Jiao Qu ◽  
Tian Yin Wang
Keyword(s):  
High Pressure ◽  
Temperature Distribution ◽  
Critical Speed ◽  
Axial Direction ◽  
Calculation Model ◽  
Rotor System ◽  
Effect Of Temperature ◽  
Critical Speeds ◽  
Calculation Results ◽  
The Impact

A dual-rotor calculation model which can expand freely in the axial direction is established in this paper, and the effects of one-dimensional axial temperature distribution on critical speeds of the dual-rotor system are analyzed with finite element method. The temperature distribution of the dual-rotor system is given referring to that of similar aero-engine rotor system. Assuming that the left end temperature remains at 0 °C, and the highest temperature on the section of the high-pressure turbine disk is 0 °C, 200 °C, 400 °C, 600 °C, and 800 °C respectively, the critical speeds of the dual-rotor system are calculated, analyzed and compared. Calculation results show that, with the increase of the highest temperature of the dual-rotor system, the reduction percentage of the critical speeds increases, and the impact on the first critical speed is most obvious. When the highest temperature is 800 °C, the first critical speed of the rotor system excited by the low-pressure rotor reduces 13.13%, and that excited by the high-pressure rotor reduces 13.49%.

scholarly journals Simplified logistics model and its application in process simulation

2020 ◽  
pp. 320-320
Author(s):  
Yiwei Chen ◽  
Guanliang Ding ◽  
Yakai Bai
Keyword(s):  
Heat Exchange ◽  
Process Simulation ◽  
Cost Model ◽  
Exchange Process ◽  
Aspen Plus ◽  
Calculation Model ◽  
Simulation Software ◽  
Simulation Based ◽  
Heat Exchange Process ◽  
Calculation Results

In order to solve the problem of complex calculation of logistics value in process simulation, based on the parameter characteristics of Aspen Plus, a simplified logistics calculation model is proposed. The comparison with exercom shows that the error of the calculation results in this paper is less than 1%, which verifies the correctness of the model. The calculation model of logistics flow provides convenience for process simulation software Aspen Plus to analyze the simulation process. Based on the logistics calculation model and the "fuel cost" model of thermal economics, a coal-fired boiler of a domestic unit is analyzed. The results show that the heat loss of the boiler mainly occurs in the process of coal decomposition and combustion, followed by the heat exchange process between flue gas and main heat exchange surface. The overall efficiency of the boiler is 46.4%.

scholarly journals PSO/GA Combined with Charge Simulation Method for the Electric Field Under Transmission Lines in 3D Calculation Model

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1140 ◽  
Author(s):  
Ru Wang ◽  
Jin Tian ◽  
Fei Wu ◽  
Zhenhua Zhang ◽  
Haishan Liu
Keyword(s):  
Electric Field ◽  
Relative Error ◽  
Field Intensity ◽  
Transmission Lines ◽  
Optimization Algorithm ◽  
Electric Field Intensity ◽  
Simulation Method ◽  
Calculation Model ◽  
Charge Simulation Method ◽  
High Voltage Engineering

The accurate calculation of electric field intensity under transmission lines is more and more important with the expansion of high voltage engineering, which largely determines the site selection and design of transmission projects. In order to get more accurate results, a methodology of a charge simulation method (CSM) combined with an intelligent optimization algorithm for a 3D calculation model is proposed in this paper. Three key points are emphasized for special mention in this optimized charge simulation method (OCSM). First, the number of sub-segments on the finite length conductor, the position and number of the simulating charge set on a sub-segment are taken as the optimization parameters for unified calculation. Secondly, the fitness function of optimization algorithm is constructed by two values, voltage relative error and electric field intensity relative error. Thirdly, a finite element method (FEM) was used to obtain the electric field intensities, which are compared with the results of the proposed algorithm. A simulation case is carried out on a 3D calculation model of 220 kV transmission lines, which verify the effectiveness of the optimization algorithm. The proposed OCSM solves the parameter optimization problem of CSM in the 3D computational model, which considers physical shape of wire span, and has the advantages of strong global search ability and higher calculation accuracy.

Study on Engine Kinematics and Dynamics Simulation Based on COSMOSMotion

2012 ◽  
Vol 503-504 ◽  
pp. 731-734
Author(s):  
Xiao Xu Liu ◽  
Min Chen ◽  
Ai Hua Tang
Keyword(s):  
Virtual Prototype ◽  
Dynamics Simulation ◽  
Kinematics And Dynamics ◽  
Engine Model ◽  
Kinematics Simulation ◽  
Simulation Based ◽  
Calculation Results ◽  
Simulation Results ◽  
Dynamics Simulations

The engine model with 4 cylinders is built by SolidWorks, the kinematics and dynamics simulations of the engine virtual prototype are done by COSMOSMotion, the results of kinematics simulation are checked, there are very small errors between the simulation results and the calculation results according to formulas. The mainly results of dynamics simulation are given. The simulation result consists with the parameters of the engine.

scholarly journals Study of the Effect of Centrifugal Force on Rotor Blade Icing Process

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Zhengzhi Wang ◽  
Chunling Zhu
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Force ◽  
Rotor Blade ◽  
Flow Direction ◽  
Three Dimensional ◽  
Simulation Method ◽  
Two Phase ◽  
Numerical Simulation Method ◽  
Calculation Results ◽  
Flow Field Characteristics

In view of the rotor icing problems, the influence of centrifugal force on rotor blade icing is investigated. A numerical simulation method of three-dimensional rotor blade icing is presented. Body-fitted grids around the rotor blade are generated using overlapping grid technology and rotor flow field characteristics are obtained by solving N-S equations. According to Eulerian two-phase flow, the droplet trajectories are calculated and droplet impingement characteristics are obtained. The mass and energy conservation equations of ice accretion model are established and a new calculation method of runback water mass based on shear stress and centrifugal force is proposed to simulate water flow and ice shape. The calculation results are compared with available experimental results in order to verify the correctness of the numerical simulation method. The influence of centrifugal force on rotor icing is calculated. The results show that the flow direction and distribution of liquid water on rotor surfaces change under the action of centrifugal force, which lead to the increasing of icing at the stagnation point and the decreasing of icing on both frozen limitations.

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